# How to simulate phase change with CFX5.7?

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 November 17, 2004, 04:49 How to simulate phase change with CFX5.7? #1 CFDFlying Guest   Posts: n/a Hi,all I have to simulate a water/vapour system. There is phase change between the two material. I have no experience about it. Could you give me some advice. A simple example is better.

 November 17, 2004, 11:29 Re: How to simulate phase change with CFX5.7? #2 Bart Prast Guest   Posts: n/a What do you want to model: dropwise condensation (heterogeneous or homogeneous) or condensation on a surface? Is it pure steam or water vapor in a gas(mixture).

 November 17, 2004, 20:35 Re: How to simulate phase change with CFX5.7? #3 CFDFlying Guest   Posts: n/a Hi, Bart Prast. I want to model dropwise condensation, and gas phase is pure water vapour. Thank you.

 November 18, 2004, 05:48 Re: How to simulate phase change with CFX5.7? #4 Bart Prast Guest   Posts: n/a http://www.cfd.com.au/cfd_conf03/papers/148Jon.pdf This shows a little but on what we are doing on that subject

 December 4, 2004, 12:46 Re: How to simulate phase change with CFX5.7? #5 Neale Guest   Posts: n/a You have three choices for this in CFX-5.7: - Equilibrium phase change model. Assumes homogeneous velocity, homogeneous energy, infinite mass transfer rate. liquid mass fraction is calculated based on mixture enthalpy and pressure, which are both calculated by the flow solver. - Eulerian Multiphase with the thermal phase change model. I suggest you run homogenous mass and momentum, inhomogeneous energy with the two resistance heat transfer model. Set the droplet side heat transfer to zero resistance, and the vapour side heat transfer to a Nusselt number or maybe one of the particle based heat transfer model. This has the limitation that the droplet diameter is fixed. You may have to play with the vapour side heat transfer model to get the right thing happening. - Lagrangian Multiphase with custom mass transfer model. This is similar to the above but you will have to code up your condensation mass transfer rate on your own. Does not have a droplet diameter limitation like Eulerian does but it's not as efficient in parallel runs.

 February 8, 2005, 11:14 how to simulate boiling with cfx5.6 #6 majid Guest   Posts: n/a if it possible, send a tutorial or help me to simulate a simple boiling phenomena, thank you

 February 11, 2005, 00:20 Re: how to simulate boiling with cfx5.6 #7 Erica Guest   Posts: n/a describe more clearly, please. i do some research as you BR, Erica

 February 19, 2005, 08:05 Re: how to simulate boiling with cfx5.6 #8 majid Guest   Posts: n/a if it possible send for me a simple tutorial of simulating a boiling phenomena, thank you

November 10, 2011, 08:32
#9
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hahha
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Quote:
 Originally Posted by Neale ;70449 You have three choices for this in CFX-5.7: - Equilibrium phase change model. Assumes homogeneous velocity, homogeneous energy, infinite mass transfer rate. liquid mass fraction is calculated based on mixture enthalpy and pressure, which are both calculated by the flow solver. - Eulerian Multiphase with the thermal phase change model. I suggest you run homogenous mass and momentum, inhomogeneous energy with the two resistance heat transfer model. Set the droplet side heat transfer to zero resistance, and the vapour side heat transfer to a Nusselt number or maybe one of the particle based heat transfer model. This has the limitation that the droplet diameter is fixed. You may have to play with the vapour side heat transfer model to get the right thing happening. - Lagrangian Multiphase with custom mass transfer model. This is similar to the above but you will have to code up your condensation mass transfer rate on your own. Does not have a droplet diameter limitation like Eulerian does but it's not as efficient in parallel runs.
can you explain about Lagrangian with condensation in detail? Have you done it successfully? I want to do it but i do not how to do ?? can you tell me your email ,my email is yxgayy@126.com. Thank you!

November 10, 2011, 08:43
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hahha
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Quote:
 Originally Posted by Bart Prast ;70341 What do you want to model: dropwise condensation (heterogeneous or homogeneous) or condensation on a surface? Is it pure steam or water vapor in a gas(mixture).
have you ever simulated heterogeneous condensation successfully using CFX ?? I have problem in setting in CFX, I think just set the user defined nucleation rate is not appropriate, it just treats the droplets formed by heterogeneous condensation as a spherical ball, not a spherical cap.Can you tell how you handle it.Thanks a lot in advance!

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